The present invention relates to a copying machine having an intermediate tray, and more particularly to a copying machine capable of guiding paper on which an image already has been formed by a copying operation into the intermediate tray and performing another copying operation on this paper sent out from the intermediate tray to enable performance of a special copying operation such as an automatic both-side copying operation, a composite copying operation, etc.
Recently, the demand for a multi-function copying machine has become strong. As a part of such demand, there has been proposed a copying machine provided with an automatic both-side copying function capable of forming images on the both sides of a piece of paper, or a composite copying function capable of forming a composite image by copying in succession desired areas of two or more original documents.
Such a copying machine generally includes an automatic both-side copying mode selection key, a composite copying mode selection key, an intermediate tray for temporarily housing, in the inside of the copying machine, paper on which an image has been once formed by a copying operation, a paper conveying passage which passes through the intermediated tray, a paper conveying passing which does not pass through the intermediate tray, and a changeover member for selectively operating the conveying passages. However, the selection of a paper feeding cassette has to be made with a cassette selection key as conventionally done. Therefore, after any of the mode selection keys have been operated, the cassette selection key is operated to select a paper feeding cassette and a print key is then operated to perform either an automatic bothside copying operation or a composite copying operation.
The intermediate tray is provided inside thereof with a width arranging mechanism for arranging, to a reference position, one end edge of paper introduced into this tray, a motor for driving the width arranging mechanism according to the type of paper selected, and a driving force transmission mechanism (Japanese Unexamined Patent Publication No. 52427/1985).
When performing an automatic both-side copying operation, the both-side copying mode selection key is operated to select the both-side copying mode, and the cassette selection key is operated to select the desired paper feeding cassette. Paper which has been sent from the paper feeding cassette and on which a previous copying operation has been performed is introduced into the intermediate tray through the paper conveying passage by the changeover member. Then, by the motor, the width arranging mechanism is driven to arrange one end edge of the paper to a reference position. The paper is then caused to pass through the paper conveying passage from the intermediate tray. A copying operation is again performed on this paper to provides for the automatic both-side copying operation without paper jam, etc.
When performing the composite copying operation, it is sufficient to operate the composite copying mode selection key instead of the both-side copying mode selection key. The composite copying operation can be performed in the same manner as in the automatic both-side copying operation.
In the copying machine arranged as described, although certain restrictions are imposed on the type of paper which can be used in the automatic both-side copying function as selected, the print key can be operated regardless of any paper feeding cassette selected. Therefore, an erroneous selection of a paper feeding cassette results in an erroneous copy. For example, when paper oriented longitudinally is passed, respective images copied on the on the opposite sides of the paper are upside down. Such paper binded at a lateral side does not have a substantial utility. This is nothing but a bad copy.
There is a wide variety of types of paper which can be set on a stacking bypass, so that the width arrangement of paper in the intermediate tray cannot be made practical for all sizes of paper. Thus, provision is made so that paper cannot be fed from the stacking bypass when the automatic both-side copying function is selected. This prevents paper from being jammed in the intermediate tray.
Therefore, when performing for example an interrupt copying operation with the automatic both-side copying function selected, it is required to remove the paper feeding cassette mounted on the copying machine and to mount a different paper feeding cassette which houses paper of the size which can be used in the interrupt copying operation. Further, upon the completion of the interrupt copying operation, it is required to change the cassette to the original cassette. This disadvantageously complicates the operation.
Further, the type of paper which can be used for the automatic both-side copying operation is considerably limited so that the valuable automatic both-side copying function cannot be put to full practical use.
In the composite copying operation, problems similar to those in the automatic both-side copying operation arise.